Hormones produced by the hypothalamic-pituitary axis are released by neurons modulated by neurotransmitter amines hypothesized to be involved in affective illness; thus, the investigation of the various aspects of neuroendocrine function in patients with affective illness and in normal controls has assumed considerable importance. Several aspects of neuroendocrine function currently under investigation in our unit include plasma studies of baseline levels, circadian patterns, variations during different phases of affective illness, and the effects of a variety of challenge stimuli and clinical and experimental drugs (including amine precursors and specific neurotransmitter agonists and antagonists). In addition, pituitary and hypothalamic peptides are being measured in cerebrospinal fluid. Some findings during the past year include: TSH response to TRH was blunted in unipolar patients compared to both normals and bipolar depressed patients. A correlation between the TSH response and CSF amine metabolites was noted. Urinary free cortisol levels were noted to differ in subgroups of patients with affective illness and to correlate with CSF amine metabolites. CSF amine metabolites were noted to differ significantly in women contingent on the status of their hypothalamic-pituitary-ovarian axis. BIBLIOGRAPHIC REFERENCES: Gold, P.W. and Goodwin, F.K.: Growth Hormone and Prolactin Response to Levodopa in Affective Illness. Lancet i:965, 1977. Gold, P.W., Goodwin, F.K., Wehr, T., Rebar, R. and Sack, R.: Growth Hormone and Prolactin Response to Levodopa in Affective Illness. Lancet ii: 1307-1308, 1976.